<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Vue的监听器Wacth</title>
</head>
<body>

<div id="app">
    <h1>{{title}}</h1>
</div>

<script src="js/vue.global.js"></script>

<script>
    var vm = Vue.createApp({
        data() {
            return {
                title: "你好，Vue3"
            }
        },
        watch: {
            title(newVal, oldVal) {
                console.log("newVal", newVal, "oldVal:", oldVal)
            }
        }
    }).mount("#app");
</script>

</body>
</html>